1. Technical Field
The present invention relates to a gas-insulated switchgear for breaking an electric power system in case of, for example, occurring any trouble in the electric power system.
2. Background Art
FIG. 5 is a partially cutaway front view of a conventional gas-insulated switchgear, and FIG. 6 is a side view taken along the line VIxe2x80x94VI in FIG. 5. In FIGS. 5 and 6, vacuum interrupters are located on the vertexes of a triangle having a horizontal base with their axes intersecting the triangle at right angles. That is, a first vacuum interrupter 1 is located on one vertex of the base, a second vacuum interrupter 2 is located on the other vertex of the base, and a third vacuum interrupter 3 is located on the remaining vertex all in a hermetically sealed container 4 filled with insulating gas. One terminal 1a of the first vacuum interrupter 1 is connected to a first bushing 5, a terminal 2a of the second vacuum interrupter 2 is connected to a second bushing 6, and a terminal 3a of the third vacuum interrupter 3 is connected to a third bushing 7. The bushings 5 to 7 are located on the axes of respective vacuum interrupters 1 to 3 and on a straight line parallel with the base of the triangle where the vacuum interrupters 1 to 3 are located. The bushings 5 to 7 are connected with bus-bars 8 to 10 respectively.
The conventional gas-insulated switchgear is constructed as described above, and consequently, in order to satisfy insulation performance between the vacuum interrupters 1 to 3 and between the first and second vacuum interrupters 1 and 2 and the hermetically sealed container 4, it is necessary to secure an insulation distance between them, and this causes a problem that it is difficult to downsize or miniaturize the gas-insulated switchgear.
Moreover, the bushings 5 to 7 are located on the straight line parallel with the base of the triangle where the vacuum interrupters 1 to 3 are located, and consequently, when the bus-bars 8 to 10 are arranged to be parallel with the base of the triangle where the vacuum interrupters 1 to 3 are located, there arises a problem that the bus-bars 8 to 10 are complicated in configuration.
The present invention was made to solve the above-discussed problems and has an object of providing a gas-insulated switchgear that can be miniaturized.
The invention has another object of providing a gas-insulated switchgear in which the bus-bars respectively connected to the bushings are simple in configuration.
A gas-insulated switchgear according to the invention is a gas-insulated switchgear in which vacuum interrupters are located on vertexes of a triangle with their axes intersecting a triangle at right angles with a first vacuum interrupter on one vertex of a base of the triangle, a second vacuum interrupter on the other vertex of the base, and a third vacuum interrupter on the remaining vertex and accommodated in a hermetically sealed container filled with an insulating gas, and one terminal of the first vacuum interrupter is connected to a first bushing, one terminal of the second vacuum interrupter is connected to a second bushing, and one terminal of the third vacuum interrupter is connected to a third bushing, wherein a distance L between outer peripheries of the first vacuum interrupter and the second vacuum interrupter is established to be smaller than an external diameter D of the vacuum interrupters, and insulating barriers are disposed between the first vacuum interrupter and the second vacuum interrupter, between the first vacuum interrupter and the hermetically sealed container, between the second vacuum interrupter and the hermetically sealed container, and between the first and second vacuum interrupters and the third vacuum interrupter.
As a result, the distance between the vacuum interrupters can be shortened, and it is possible to diminish the width of the hermetically sealed container and miniaturize the gas-insulated switchgear as a whole.
It is preferable that the first bushing is located on the axis of the first vacuum interrupter and on any one of three different virtual lines parallel with the base of the triangle, the second bushing is located on the axis of the second vacuum interrupter and on any one of the virtual lines excluding the virtual line where the first bushing is located, and the third bushing is located on the axis of the third vacuum interrupter and on the remaining virtual line.
As a result, although the bushings are located on the straight lines parallel with the base of the triangle where the vacuum interrupters are located, the bus-bars can be arranged forming straight lines. Consequently, it is possible to simplify the configurations of the bus-bars as a whole.
It is also preferable that the third bushing is located on the axis of the third vacuum interrupter and on any one of three different virtual lines parallel with the base of the triangle nearest to one terminal of the third vacuum interrupter, the first bushing is located on the axis of the first vacuum interrupter and on one of the virtual lines excluding the virtual line where the third bushing is located, and the second bushing is located on the axis of the second vacuum interrupter and on the remaining virtual line.
As a result, it is possible to diminish the size in the direction of extending the bushings.